with WOW using at least 2 cores by itself, I would get a quad core cpu so that it will be efficient while running windows and other tasks in the backround. What system are you using now? You may be better off simply upgrading that one and also save money

Paired a non-reference short 270x (was only like $10 more then the 270) with a 4430 on an Asus ITX mobo in a 250D for a killer little mid range rig for a friend of mine, surprisingly fast for its price.